A novel long noncoding RNA AC125257.1 facilitates colorectal cancer progression by targeting miR-133a-3p/CASC5 axis

Colorectal cancer (CRC) is a common malignant gastrointestinal tumor. Long noncoding RNAs (lncRNAs) are revealed to be critically involved in CRC progression, providing new direction for exploring the pathogenesis of CRC. This study aimed to explore the biological functions and regulatory mechanisms of lncRNA AC125257.1 in CRC. Western blotting and reverse-transcription quantitative polymerase chain reaction were used for the measurement of gene expression. Cell counting kit-8 assay and flow cytometry analysis were used to explore the effects of AC125257.1 on CRC cell viability and apoptosis. RNA pull-down and immunoprecipitation assays were performed for validating the binding between AC125257.1 and its potential downstream microRNA. Results showed that lncRNA AC125257.1 expression was upregulated in CRC cells and tumor tissues. AC125257.1 enhanced cell viability and suppressed apoptosis of CRC cells. Moreover, the knockdown of AC125257.1 suppressed CRC progression in vitro and inhibited tumor growth in vivo. miR-133a-3p was revealed to bind with AC125257.1 in CRC cells. CASC5 was proved to be targeted by miR-133a-3p. Moreover, rescue assays indicated that the knockdown of AC125257.1 suppressed the pathogenic overexpression of CASC5. To conclude, AC125257.1 aggravates CRC development via miR-873-5p/CASC5 axis. Our findings might suggest a novel perspective that AC125257.1 may become the target for CRC treatment.